Light or heavy-duty trailers require an energy absorbing system to support the frame and cargo from the wheels. This system is permanently mounted to the vehicular frame, which generally includes shock absorbers to dampen excessive spring action and vibrations. Serviceability of the system, whether replacement or repair, is a time-consuming and often expensive procedure. This is particularly true where major parts or the whole system requires replacement. Most axle systems require sufficient clearance from the vehicular frame for operation, which increases trailer height and resulting center of gravity. Because of this and the size required for proper operation, a significant amount of unsprung mass is present, contributing to inferior ride and control quality.
Manufactured homes that are road mobile have either an integral frame chassis or are carried on a special transporter. Both designs require three or more axles, especially the transporter as the finished home is heavier. Because of code requirements for proper travel, suspension system costs can become considerable. Integral frame homes rarely travel more than once, from point of manufacture to site location. Axles remain with the home and the tire and wheel assemblies are the only recoverable costs. Although the transporter is used repeatedly for home delivery, the system and tire wear is excessive on return trips.
Aside from vehicles, propeller shafts, like PTO (power take-off) shafts, are required to absorb and transmit high inertial and shock transient loads. Resulting loads are hard on entire drive line machinery. When failure does occur, rotating shaft damage can be excessive and severe. Absorption of transient loads allows for smoother and safer operation and reduced servicing costs.